Although it is well recognized that continuous administration of gonadotropin-releasing hormone agonist (GnRHa) induces pituitary desensitization, the precise molecular mechanism of this phenomenon is still unclear. To test the hypothesis that pituitary gonadotroph desensitization is mediated by a change in GnRH receptor (GnRH-R) gene expression, the GnRH-R mRNA concentration was analyzed in im...

BACKGROUND The aim of this study was to assess the effect of an individualized GnRH antagonist regimen on folliculogenesis. METHODS In a multicentre, randomized, clinical trial, IVF/ICSI patients were allocated to a standard regimen, in which they received daily 0.25 mg GnRH antagonist ganirelix (Orgalutran) from the 6th day of stimulation onward (fixed regimen n = 102) or to an individualize...

We report on ovarian dysfunction in a 3-year-old girl with blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES). A gonadotropin releasing hormone test showed hyperresponses of luteinizing hormone (<0.2-->7.2 mIU/ml) and follicle-stimulating hormone (7.1-->44.8 mIU/ml), and a human menopause gonadotropin test yielded no estradiol response (13-->11 pg/ml). The results suggest that pr...

Clinical findings and endocrine studies are reported concerning six subjects (from two pedigrees) suffering from isolated hypogonadotropic hypogonadism. Their complete lack of any gonadotropin response to clomiphene stimulation, together with positive responses of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) to LH-releasing-hormone stimulation (LH-RH) provide evidence for a h...

The human gonadotropin-releasing hormone (GnRH) precursor consists of the GnRH sequence followed by a 59-amino acid carboxyl-terminal extension. A 56-amino acid peptide within this extension has been shown to stimulate gonadotropin release, and this activity has been localized to its amino-terminal region. A series of seven overlapping peptide fragments corresponding to the first 24 amino acids...